title: sshd_config(5)

summary: OpenSSH SSH daemon configuration file

text:
# sshd_config(5)

## NAME
sshd_config — OpenSSH SSH daemon configuration file

## DESCRIPTION
sshd(8) reads configuration data from /etc/openssh/sshd_config (or the file specified with -f on the command line). The file contains keyword-argument pairs, one per line. For each keyword, the first obtained value will be used. Lines starting with ‘#’ and empty lines are interpreted as comments. Arguments may optionally be enclosed in double quotes (") in order to represent arguments containing spaces.

The possible keywords and their meanings are as follows (note that keywords are case-insensitive and arguments are case-sensitive):

AcceptEnv

Specifies what environment variables sent by the client will be copied into the session's environ(7). See SendEnv and SetEnv in ssh_config(5) for how to configure the client. The TERM environment variable is always accepted whenever the client requests a pseudo-terminal as it is required by the protocol. Variables are specified by name, which may contain the wildcard characters ‘*’ and ‘?’. Multiple environment variables may be separated by whitespace or spread across multiple AcceptEnv directives. Be warned that some environment variables could be used to bypass restricted user environments. For this reason, care should be taken in the use of this directive. The default is not to accept any environment variables.

AddressFamily

Specifies which address family should be used by sshd(8). Valid arguments are any (the default), inet (use IPv4 only), or inet6 (use IPv6 only).

AllowAgentForwarding

Specifies whether ssh-agent(1) forwarding is permitted. The default is yes. Note that disabling agent forwarding does not improve security unless users are also denied shell access, as they can always install their own forwarders.

AllowGroups

This keyword can be followed by a list of group name patterns, separated by spaces. If specified, login is allowed only for users whose primary group or supplementary group list matches one of the patterns. Only group names are valid; a numerical group ID is not recognized. By default, login is allowed for all groups. The allow/deny directives are processed in the following order: DenyUsers, AllowUsers, DenyGroups, and finally AllowGroups. See PATTERNS in ssh_config(5) for more information on patterns.

AllowStreamLocalForwarding

Specifies whether StreamLocal (Unix-domain socket) forwarding is permitted. The available options are yes (the default) or all to allow StreamLocal forwarding, no to prevent all StreamLocal forwarding, local to allow local (from the perspective of ssh(1)) forwarding only or remote to allow remote forwarding only. Note that disabling StreamLocal forwarding does not improve security unless users are also denied shell access, as they can always install their own forwarders.

AllowTcpForwarding

Specifies whether TCP forwarding is permitted. The available options are yes (the default) or all to allow TCP forwarding, no to prevent all TCP forwarding, local to allow local (from the perspective of ssh(1)) forwarding only or remote to allow remote forwarding only. Note that disabling TCP forwarding does not improve security unless users are also denied shell access, as they can always install their own forwarders.

AllowUsers

This keyword can be followed by a list of user name patterns, separated by spaces. If specified, login is allowed only for user names that match one of the patterns. Only user names are valid; a numerical user ID is not recognized. By default, login is allowed for all users. If the pattern takes the form USER@HOST then USER and HOST are separately checked, restricting logins to particular users from particular hosts. HOST criteria may additionally contain addresses to match in CIDR address/masklen format. The allow/deny directives are processed in the following order: DenyUsers, AllowUsers, DenyGroups, and finally AllowGroups. See PATTERNS in ssh_config(5) for more information on patterns.

AuthenticationMethods

Specifies the authentication methods that must be successfully completed for a user to be granted access. This option must be followed by one or more lists of comma-separated authentication method names, or by the single string any to indicate the default behaviour of accepting any single authentication method. If the default is overridden, then successful authentication requires completion of every method in at least one of these lists. For example, "publickey,password publickey,keyboard-interactive" would require the user to complete public key authentication, followed by either password or keyboard interactive authentication. Only methods that are next in one or more lists are offered at each stage, so for this example it would not be possible to attempt password or keyboard-interactive authentication before public key.

For keyboard interactive authentication it is also possible to restrict authentication to a specific device by appending a colon followed by the device identifier bsdauth or pam. depending on the server configuration. For example, "keyboard-interactive:bsdauth" would restrict keyboard interactive authentication to the bsdauth device.

If the publickey method is listed more than once, sshd(8) verifies that keys that have been used successfully are not reused for subsequent authentications. For example, "publickey,publickey" requires successful authentication using two different public keys.

Note that each authentication method listed should also be explicitly enabled in the configuration.

The available authentication methods are: "gssapi-with-mic", "hostbased", "keyboard-interactive", "none" (used for access to password-less accounts when PermitEmptyPasswords is enabled), "password" and "publickey".

AuthorizedKeysCommand

Specifies a program to be used to look up the user's public keys. The program must be owned by root, not writable by group or others and specified by an absolute path. Arguments to AuthorizedKeysCommand accept the tokens described in the TOKENS section. If no arguments are specified then the username of the target user is used. The program should produce on standard output zero or more lines of authorized_keys output (see AUTHORIZED_KEYS in sshd(8)). If a key supplied by AuthorizedKeysCommand does not successfully authenticate and authorize the user then public key authentication continues using the usual AuthorizedKeysFile files. By default, no AuthorizedKeysCommand is run.

AuthorizedKeysCommandUser

Specifies the user under whose account the AuthorizedKeysCommand is run. It is recommended to use a dedicated user that has no other role on the host than running authorized keys commands. If AuthorizedKeysCommand is specified but AuthorizedKeysCommandUser is not, then sshd(8) will refuse to start.

AuthorizedKeysFile

Specifies the file that contains the public keys used for user authentication. The format is described in the AUTHORIZED_KEYS FILE FORMAT section of sshd(8). Arguments to AuthorizedKeysFile accept the tokens described in the TOKENS section. After expansion, AuthorizedKeysFile is taken to be an absolute path or one relative to the user's home directory. Multiple files may be listed, separated by whitespace. Alternately this option may be set to none to skip checking for user keys in files. The default is "/etc/openssh/authorized_keys/%u /etc/openssh/authorized_keys2/%u .ssh/authorized_keys .ssh/authorized_keys2".

AuthorizedPrincipalsCommand

Specifies a program to be used to generate the list of allowed certificate principals as per AuthorizedPrincipalsFile. The program must be owned by root, not writable by group or others and specified by an absolute path. Arguments to AuthorizedPrincipalsCommand accept the tokens described in the TOKENS section. If no arguments are specified then the username of the target user is used. The program should produce on standard output zero or more lines of AuthorizedPrincipalsFile output. If either AuthorizedPrincipalsCommand or AuthorizedPrincipalsFile is specified, then certificates offered by the client for authentication must contain a principal that is listed. By default, no AuthorizedPrincipalsCommand is run.

AuthorizedPrincipalsCommandUser

Specifies the user under whose account the AuthorizedPrincipalsCommand is run. It is recommended to use a dedicated user that has no other role on the host than running authorized principals commands. If AuthorizedPrincipalsCommand is specified but AuthorizedPrincipalsCommandUser is not, then sshd(8) will refuse to start.

AuthorizedPrincipalsFile

Specifies a file that lists principal names that are accepted for certificate authentication. When using certificates signed by a key listed in TrustedUserCAKeys, this file lists names, one of which must appear in the certificate for it to be accepted for authentication. Names are listed one per line preceded by key options (as described in AUTHORIZED_KEYS FILE FORMAT in sshd(8)). Empty lines and comments starting with ‘#’ are ignored. Arguments to AuthorizedPrincipalsFile accept the tokens described in the TOKENS section. After expansion, AuthorizedPrincipalsFile is taken to be an absolute path or one relative to the user's home directory. The default is none, i.e. not to use a principals file – in this case, the username of the user must appear in a certificate's principals list for it to be accepted.

Note that AuthorizedPrincipalsFile is only used when authentication proceeds using a CA listed in TrustedUserCAKeys and is not consulted for certification authorities trusted via ~/.ssh/authorized_keys or /etc/openssh/authorized_keys/, though the principals= key option offers a similar facility (see sshd(8) for details).

Banner

The contents of the specified file are sent to the remote user before authentication is allowed. If the argument is none then no banner is displayed. By default, no banner is displayed.

CASignatureAlgorithms

Specifies which algorithms are allowed for signing of certificates by certificate authorities (CAs). The default is:

```
ecdsa-sha2-nistp256.ecdsa-sha2-nistp384,ecdsa-sha2-nistp521,
ssh-ed25519,rsa-sha2-512,rsa-sha2-256,ssh-rsa
```

Certificates signed using other algorithms will not be accepted for public key or host-based authentication.

ChallengeResponseAuthentication

Specifies whether challenge-response authentication is allowed (e.g. via PAM). The default is no.

ChrootDirectory

Specifies the pathname of a directory to chroot(2) to after authentication. At session startup sshd(8) checks that all components of the pathname are root-owned directories which are not writable by any other user or group. After the chroot, sshd(8) changes the working directory to the user's home directory. Arguments to ChrootDirectory accept the tokens described in the TOKENS section. The ChrootDirectory must contain the necessary files and directories to support the user's session. For an interactive session this requires at least a shell, typically sh(1), and basic /dev nodes such as null(4), zero(4), stdin(4), stdout(4), stderr(4), and tty(4) devices. For file transfer sessions using SFTP no additional configuration of the environment is necessary if the in-process sftp-server is used, though sessions which use logging may require /dev/log inside the chroot directory on some operating systems (see sftp-server(8) for details).

For safety, it is very important that the directory hierarchy be prevented from modification by other processes on the system (especially those outside the jail). Misconfiguration can lead to unsafe environments which sshd(8) cannot detect.

The default is none, indicating not to chroot(2).

Ciphers

Specifies the ciphers allowed. Multiple ciphers must be comma-separated. If the specified value begins with a ‘+’ character, then the specified ciphers will be appended to the default set instead of replacing them. If the specified value begins with a ‘-’ character, then the specified ciphers (including wildcards) will be removed from the default set instead of replacing them. The supported ciphers are:

- 3des-cbc

- aes128-cbc

- aes192-cbc

- aes256-cbc

- aes128-ctr

- aes192-ctr

- aes256-ctr

- aes128-gcm@openssh.com

- aes256-gcm@openssh.com

- chacha20-poly1305@openssh.com

The default is:

```
chacha20-poly1305@openssh.com,
aes256-gcm@openssh.com,aes128-gcm@openssh.com,
aes256-ctr,aes192-ctr,aes128-ctr
```

The list of available ciphers may also be obtained using "ssh -Q cipher".

ClientAliveCountMax

Sets the number of client alive messages which may be sent without sshd(8) receiving any messages back from the client. If this threshold is reached while client alive messages are being sent, sshd will disconnect the client, terminating the session. It is important to note that the use of client alive messages is very different from TCPKeepAlive. The client alive messages are sent through the encrypted channel and therefore will not be spoofable. The TCP keepalive option enabled by TCPKeepAlive is spoofable. The client alive mechanism is valuable when the client or server depend on knowing when a connection has become inactive. The default value is 3. If ClientAliveInterval is set to 15, and ClientAliveCountMax is left at the default, unresponsive SSH clients will be disconnected after approximately 45 seconds.

ClientAliveInterval

Sets a timeout interval in seconds after which if no data has been received from the client, sshd(8) will send a message through the encrypted channel to request a response from the client. The default is 0, indicating that these messages will not be sent to the client.

Compression

Specifies whether compression is enabled after the user has authenticated successfully. The argument must be yes, delayed (a legacy synonym for yes) or no. The default is yes.

DenyGroups

This keyword can be followed by a list of group name patterns, separated by spaces. Login is disallowed for users whose primary group or supplementary group list matches one of the patterns. Only group names are valid; a numerical group ID is not recognized. By default, login is allowed for all groups. The allow/deny directives are processed in the following order: DenyUsers, AllowUsers, DenyGroups, and finally AllowGroups. See PATTERNS in ssh_config(5) for more information on patterns.

DenyUsers

This keyword can be followed by a list of user name patterns, separated by spaces. Login is disallowed for user names that match one of the patterns. Only user names are valid; a numerical user ID is not recognized. By default, login is allowed for all users. If the pattern takes the form USER@HOST then USER and HOST are separately checked, restricting logins to particular users from particular hosts. HOST criteria may additionally contain addresses to match in CIDR address/masklen format. The allow/deny directives are processed in the following order: DenyUsers, AllowUsers, DenyGroups, and finally AllowGroups. See PATTERNS in ssh_config(5) for more information on patterns.

DisableForwarding

Disables all forwarding features, including X11, ssh-agent(1), TCP and StreamLocal. This option overrides all other forwarding-related options and may simplify restricted configurations.

ExposeAuthInfo

Writes a temporary file containing a list of authentication methods and public credentials (e.g. keys) used to authenticate the user. The location of the file is exposed to the user session through the SSH_USER_AUTH environment variable. The default is no.

FingerprintHash

Specifies the hash algorithm used when logging key fingerprints. Valid options are: md5 and sha256. The default is sha256.

ForceCommand

Forces the execution of the command specified by ForceCommand, ignoring any command supplied by the client and ~/.ssh/rc if present. The command is invoked by using the user's login shell with the -c option. This applies to shell, command, or subsystem execution. It is most useful inside a Match block. The command originally supplied by the client is available in the SSH_ORIGINAL_COMMAND environment variable. Specifying a command of internal-sftp will force the use of an in-process SFTP server that requires no support files when used with ChrootDirectory. The default is none.

GatewayPorts

Specifies whether remote hosts are allowed to connect to ports forwarded for the client. By default, sshd(8) binds remote port forwardings to the loopback address. This prevents other remote hosts from connecting to forwarded ports. GatewayPorts can be used to specify that sshd should allow remote port forwardings to bind to non-loopback addresses, thus allowing other hosts to connect. The argument may be no to force remote port forwardings to be available to the local host only, yes to force remote port forwardings to bind to the wildcard address, or clientspecified to allow the client to select the address to which the forwarding is bound. The default is no.

GSSAPIAuthentication

Specifies whether user authentication based on GSSAPI is allowed. The default is no.

GSSAPICleanupCredentials

Specifies whether to automatically destroy the user's credentials cache on logout. The default is yes.

GSSAPIStrictAcceptorCheck

Determines whether to be strict about the identity of the GSSAPI acceptor a client authenticates against. If set to yes then the client must authenticate against the host service on the current hostname. If set to no then the client may authenticate against any service key stored in the machine's default store. This facility is provided to assist with operation on multi homed machines. The default is yes.

HostbasedAcceptedKeyTypes

Specifies the key types that will be accepted for hostbased authentication as a list of comma-separated patterns. Alternately if the specified value begins with a ‘+’ character, then the specified key types will be appended to the default set instead of replacing them. If the specified value begins with a ‘-’ character, then the specified key types (including wildcards) will be removed from the default set instead of replacing them. The default for this option is the same as for HostKeyAlgorithms option. The list of available key types may also be obtained using "ssh -Q key".

HostbasedAuthentication

Specifies whether rhosts or /etc/hosts.equiv authentication together with successful public key client host authentication is allowed (host-based authentication). The default is no.

HostbasedUsesNameFromPacketOnly

Specifies whether or not the server will attempt to perform a reverse name lookup when matching the name in the ~/.shosts, ~/.rhosts, and /etc/hosts.equiv files during HostbasedAuthentication. A setting of yes means that sshd(8) uses the name supplied by the client rather than attempting to resolve the name from the TCP connection itself. The default is no.

HostCertificate

Specifies a file containing a public host certificate. The certificate's public key must match a private host key already specified by HostKey. The default behaviour of sshd(8) is not to load any certificates.

HostKey

Specifies a file containing a private host key used by SSH. The defaults are /etc/openssh/ssh_host_ecdsa_key, /etc/openssh/ssh_host_ed25519_key and /etc/openssh/ssh_host_rsa_key. Note that sshd(8) will refuse to use a file if it is group/world-accessible and that the HostKeyAlgorithms option restricts which of the keys are actually used by sshd(8).

It is possible to have multiple host key files. It is also possible to specify public host key files instead. In this case operations on the private key will be delegated to an ssh-agent(1).

HostKeyAgent

Identifies the UNIX-domain socket used to communicate with an agent that has access to the private host keys. If the string "SSH_AUTH_SOCK" is specified, the location of the socket will be read from the SSH_AUTH_SOCK environment variable.

HostKeyAlgorithms

Specifies the host key algorithms that the server offers. The default for this option is:

```
ecdsa-sha2-nistp256-cert-v01@openssh.com,
ecdsa-sha2-nistp384-cert-v01@openssh.com,
ecdsa-sha2-nistp521-cert-v01@openssh.com,
ssh-ed25519-cert-v01@openssh.com,
rsa-sha2-512-cert-v01@openssh.com,rsa-sha2-256-cert-v01@openssh.com,
ssh-rsa-cert-v01@openssh.com,
ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521,
ssh-ed25519,rsa-sha2-512,rsa-sha2-256,ssh-rsa
```

The list of available key types may also be obtained using "ssh -Q key".

IgnoreRhosts

Specifies that .rhosts and .shosts files will not be used in HostbasedAuthentication. /etc/hosts.equiv and /etc/openssh/shosts.equiv are still used. The default is yes.

IgnoreUserKnownHosts

Specifies whether sshd(8) should ignore the user's ~/.ssh/known_hosts during HostbasedAuthentication and use only the system-wide known hosts file /etc/ssh/known_hosts. The default is no.

IPQoS

Specifies the IPv4 type-of-service or DSCP class for the connection. Accepted values are af11, af12, af13, af21, af22, af23, af31, af32, af33, af41, af42, af43, cs0, cs1, cs2, cs3, cs4, cs5, cs6, cs7, ef, lowdelay, throughput, reliability, a numeric value, or none to use the operating system default. This option may take one or two arguments, separated by whitespace. If one argument is specified, it is used as the packet class unconditionally. If two values are specified, the first is automatically selected for interactive sessions and the second for non-interactive sessions. The default is af21 (Low-Latency Data) for interactive sessions and cs1 (Lower Effort) for non-interactive sessions.

KbdInteractiveAuthentication

Specifies whether to allow keyboard-interactive authentication. The argument to this keyword must be yes or no. The default is to use whatever value ChallengeResponseAuthentication is set to (by default yes).

KerberosAuthentication

Specifies whether the password provided by the user for PasswordAuthentication will be validated through the Kerberos KDC. To use this option, the server needs a Kerberos servtab which allows the verification of the KDC's identity. The default is no.

KerberosGetAFSToken

If AFS is active and the user has a Kerberos 5 TGT, attempt to acquire an AFS token before accessing the user's home directory. The default is no.

KerberosOrLocalPasswd

If password authentication through Kerberos fails then the password will be validated via any additional local mechanism such as /etc/passwd. The default is yes.

KerberosTicketCleanup

Specifies whether to automatically destroy the user's ticket cache file on logout. The default is yes.

KexAlgorithms

Specifies the available KEX (Key Exchange) algorithms. Multiple algorithms must be comma-separated. Alternately if the specified value begins with a ‘+’ character, then the specified methods will be appended to the default set instead of replacing them. If the specified value begins with a ‘-’ character, then the specified methods (including wildcards) will be removed from the default set instead of replacing them. The supported algorithms are:

- curve25519-sha256

- curve25519-sha256@libssh.org

- diffie-hellman-group1-sha1

- diffie-hellman-group14-sha1

- diffie-hellman-group14-sha256

- diffie-hellman-group16-sha512

- diffie-hellman-group18-sha512

- diffie-hellman-group-exchange-sha1

- diffie-hellman-group-exchange-sha256

- ecdh-sha2-nistp256

- ecdh-sha2-nistp384

- ecdh-sha2-nistp521

The default is:

```
curve25519-sha256,curve25519-sha256@libssh.org,
ecdh-sha2-nistp521,ecdh-sha2-nistp384,ecdh-sha2-nistp256,
diffie-hellman-group-exchange-sha256,
diffie-hellman-group16-sha512,diffie-hellman-group18-sha512,
diffie-hellman-group14-sha256,diffie-hellman-group14-sha1
```

The list of available key exchange algorithms may also be obtained using "ssh -Q kex".

ListenAddress

Specifies the local addresses sshd(8) should listen on. The following forms may be used:

- ListenAddress hostname|address [rdomain domain]

- ListenAddress hostname:port [rdomain domain]

- ListenAddress IPv4_address:port [rdomain domain]

- ListenAddress [hostname|address]:port [rdomain domain]

The optional rdomain qualifier requests sshd(8) listen in an explicit routing domain. If port is not specified, sshd will listen on the address and all Port options specified. The default is to listen on all local addresses on the current default routing domain. Multiple ListenAddress options are permitted. For more information on routing domains, see rdomain(4).

LoginGraceTime

The server disconnects after this time if the user has not successfully logged in. If the value is 0, there is no time limit. The default is 120 seconds.

LogLevel

Gives the verbosity level that is used when logging messages from sshd(8). The possible values are: QUIET, FATAL, ERROR, INFO, VERBOSE, DEBUG, DEBUG1, DEBUG2, and DEBUG3. The default is INFO. DEBUG and DEBUG1 are equivalent. DEBUG2 and DEBUG3 each specify higher levels of debugging output. Logging with a DEBUG level violates the privacy of users and is not recommended.

MACs

Specifies the available MAC (message authentication code) algorithms. The MAC algorithm is used for data integrity protection. Multiple algorithms must be comma-separated. If the specified value begins with a ‘+’ character, then the specified algorithms will be appended to the default set instead of replacing them. If the specified value begins with a ‘-’ character, then the specified algorithms (including wildcards) will be removed from the default set instead of replacing them. The algorithms that contain "-etm" calculate the MAC after encryption (encrypt-then-mac). These are considered safer and their use recommended. The supported MACs are:

- hmac-md5

- hmac-md5-96

- hmac-sha1

- hmac-sha1-96

- hmac-sha2-256

- hmac-sha2-512

- umac-64@openssh.com

- umac-128@openssh.com

- hmac-md5-etm@openssh.com

- hmac-md5-96-etm@openssh.com

- hmac-sha1-etm@openssh.com

- hmac-sha1-96-etm@openssh.com

- hmac-sha2-256-etm@openssh.com

- hmac-sha2-512-etm@openssh.com

- umac-64-etm@openssh.com

- umac-128-etm@openssh.com

The default is:

```
umac-128-etm@openssh.com,umac-64-etm@openssh.com,
hmac-sha2-512-etm@openssh.com,hmac-sha2-256-etm@openssh.com,
hmac-sha1-etm@openssh.com,
umac-128@openssh.com,umac-64@openssh.com,
hmac-sha2-512,hmac-sha2-256,hmac-sha1
```

The list of available MAC algorithms may also be obtained using "ssh -Q mac".

Match

Introduces a conditional block. If all of the criteria on the Match line are satisfied, the keywords on the following lines override those set in the global section of the config file, until either another Match line or the end of the file. If a keyword appears in multiple Match blocks that are satisfied, only the first instance of the keyword is applied. The arguments to Match are one or more criteria-pattern pairs or the single token All which matches all criteria. The available criteria are User, Group, Host, LocalAddress, LocalPort, RDomain, and Address (with RDomain representing the rdomain(4) on which the connection was received.)

The match patterns may consist of single entries or comma-separated lists and may use the wildcard and negation operators described in the PATTERNS section of ssh_config(5).

The patterns in an Address criteria may additionally contain addresses to match in CIDR address/masklen format, such as 192.0.2.0/24 or 2001:db8::/32. Note that the mask length provided must be consistent with the address - it is an error to specify a mask length that is too long for the address or one with bits set in this host portion of the address. For example, 192.0.2.0/33 and 192.0.2.0/8, respectively.

Only a subset of keywords may be used on the lines following a Match keyword. Available keywords are AcceptEnv, AllowAgentForwarding, AllowGroups, AllowStreamLocalForwarding, AllowTcpForwarding, AllowUsers, AuthenticationMethods, AuthorizedKeysCommand, AuthorizedKeysCommandUser, AuthorizedKeysFile, AuthorizedPrincipalsCommand, AuthorizedPrincipalsCommandUser, AuthorizedPrincipalsFile, Banner, ChrootDirectory, ClientAliveCountMax, ClientAliveInterval, DenyGroups, DenyUsers, ForceCommand, GatewayPorts, GSSAPIAuthentication, HostbasedAcceptedKeyTypes, HostbasedAuthentication, HostbasedUsesNameFromPacketOnly, IPQoS, KbdInteractiveAuthentication, KerberosAuthentication, LogLevel, MaxAuthTries, MaxSessions, PasswordAuthentication, PermitEmptyPasswords, PermitListen, PermitOpen, PermitRootLogin, PermitTTY, PermitTunnel, PermitUserRC, PubkeyAcceptedKeyTypes, PubkeyAuthentication, RekeyLimit, RevokedKeys, RDomain, SetEnv, StreamLocalBindMask, StreamLocalBindUnlink, TrustedUserCAKeys, X11DisplayOffset, X11Forwarding and X11UseLocalHost.

MaxAuthTries

Specifies the maximum number of authentication attempts permitted per connection. Once the number of failures reaches half this value, additional failures are logged. The default is 6.

MaxSessions

Specifies the maximum number of open shell, login or subsystem (e.g. sftp) sessions permitted per network connection. Multiple sessions may be established by clients that support connection multiplexing. Setting MaxSessions to 1 will effectively disable session multiplexing, whereas setting it to 0 will prevent all shell, login and subsystem sessions while still permitting forwarding. The default is 10.

MaxStartups

Specifies the maximum number of concurrent unauthenticated connections to the SSH daemon. Additional connections will be dropped until authentication succeeds or the LoginGraceTime expires for a connection. The default is 10:30:100. Alternatively, random early drop can be enabled by specifying the three colon separated values start:rate:full (e.g. "10:30:60"). sshd(8) will refuse connection attempts with a probability of rate/100 (30%) if there are currently start (10) unauthenticated connections. The probability increases linearly and all connection attempts are refused if the number of unauthenticated connections reaches full (60).

PasswordAuthentication

Specifies whether password authentication is allowed. The default is yes.

PermitEmptyPasswords

When password authentication is allowed, it specifies whether the server allows login to accounts with empty password strings. The default is no.

PermitListen

Specifies the addresses/ports on which a remote TCP port forwarding may listen. The listen specification must be one of the following forms:

- PermitListen port

- PermitListen host:port

Multiple permissions may be specified by separating them with whitespace. An argument of any can be used to remove all restrictions and permit any listen requests. An argument of none can be used to prohibit all listen requests. The host name may contain wildcards as described in the PATTERNS section in ssh_config(5). The wildcard ‘*’ can also be used in place of a port number to allow all ports. By default all port forwarding listen requests are permitted. Note that the GatewayPorts option may further restrict which addresses may be listened on. Note also that ssh(1) will request a listen host of “localhost” if no listen host was specifically requested, and this this name is treated differently to explicit localhost addresses of “127.0.0.1” and “::1”.

PermitOpen

Specifies the destinations to which TCP port forwarding is permitted. The forwarding specification must be one of the following forms:

- PermitOpen host:port

- PermitOpen IPv4_addr:port

- PermitOpen [IPv6_addr]:port

Multiple forwards may be specified by separating them with whitespace. An argument of any can be used to remove all restrictions and permit any forwarding requests. An argument of none can be used to prohibit all forwarding requests. The wildcard ‘*’ can be used for host or port to allow all hosts or ports, respectively. By default all port forwarding requests are permitted.

PermitRootLogin

Specifies whether root can log in using ssh(1). The argument must be yes, prohibit-password, forced-commands-only, or no. The default is without-password. If this option is set to prohibit-password (or its deprecated alias, without-password), password and keyboard-interactive authentication are disabled for root.

If this option is set to forced-commands-only, root login with public key authentication will be allowed, but only if the command option has been specified (which may be useful for taking remote backups even if root login is normally not allowed). All other authentication methods are disabled for root.

If this option is set to no, root is not allowed to log in.

PermitTTY

Specifies whether pty(4) allocation is permitted. The default is yes.

PermitTunnel

Specifies whether tun(4) device forwarding is allowed. The argument must be yes, point-to-point (layer 3), ethernet (layer 2), or no. Specifying yes permits both point-to-point and ethernet. The default is no. Independent of this setting, the permissions of the selected tun(4) device must allow access to the user.

PermitUserEnvironment

Specifies whether ~/.ssh/environment and environment= options in ~/.ssh/authorized_keys and /etc/openssh/authorized_keys/ are processed by sshd(8). Valid options are yes, no or a pattern-list specifying which environment variable names to accept (for example "LANG,LC_*"). The default is no. Enabling environment processing may enable users to bypass access restrictions in some configurations using mechanisms such as LD_PRELOAD.

PermitUserRC

Specifies whether any ~/.ssh/rc file is executed. The default is yes.

PidFile

Specifies the file that contains the process ID of the SSH daemon, or none to not write one. The default is /var/run/sshd.pid.

Port

Specifies the port number that sshd(8) listens on. The default is 22. Multiple options of this type are permitted. See also ListenAddress.

PrintLastLog

Specifies whether sshd(8) should print the date and time of the last user login when a user logs in interactively. The default is yes.

PrintMotd

Specifies whether sshd(8) should print /etc/motd when a user logs in interactively. (On some systems it is also printed by the shell, /etc/profile, or equivalent.) The default is yes.

PubkeyAcceptedKeyTypes

Specifies the key types that will be accepted for public key authentication as a list of comma-separated patterns. Alternately if the specified value begins with a ‘+’ character, then the specified key types will be appended to the default set instead of replacing them. If the specified value begins with a ‘-’ character, then the specified key types (including wildcards) will be removed from the default set instead of replacing them. The default for this option is the same as for HostKeyAlgorithms option. The list of available key types may also be obtained using "ssh -Q key".

PubkeyAuthentication

Specifies whether public key authentication is allowed. The default is yes.

RekeyLimit

Specifies the maximum amount of data that may be transmitted before the session key is renegotiated, optionally followed a maximum amount of time that may pass before the session key is renegotiated. The first argument is specified in bytes and may have a suffix of ‘K’, ‘M’, or ‘G’ to indicate Kilobytes, Megabytes, or Gigabytes, respectively. The default is between ‘1G’ and ‘4G’, depending on the cipher. The optional second value is specified in seconds and may use any of the units documented in the TIME FORMATS section. The default value for RekeyLimit is default none, which means that rekeying is performed after the cipher's default amount of data has been sent or received and no time based rekeying is done.

RevokedKeys

Specifies revoked public keys file, or none to not use one. Keys listed in this file will be refused for public key authentication. Note that if this file is not readable, then public key authentication will be refused for all users. Keys may be specified as a text file, listing one public key per line, or as an OpenSSH Key Revocation List (KRL) as generated by ssh-keygen(1). For more information on KRLs, see the KEY REVOCATION LISTS section in ssh-keygen(1).

RDomain

Specifies an explicit routing domain that is applied after authentication has completed. The user session, as well and any forwarded or listening IP sockets, will be bound to this rdomain(4). If the routing domain is set to %D, then the domain in which the incoming connection was received will be applied.

SetEnv

Specifies one or more environment variables to set in child sessions started by sshd(8) as “NAME=VALUE”. The environment value may be quoted (e.g. if it contains whitespace characters). Environment variables set by SetEnv override the default environment and any variables specified by the user via AcceptEnv or PermitUserEnvironment.

StreamLocalBindMask

Sets the octal file creation mode mask (umask) used when creating a Unix-domain socket file for local or remote port forwarding. This option is only used for port forwarding to a Unix-domain socket file. The default value is 0177, which creates a Unix-domain socket file that is readable and writable only by the owner. Note that not all operating systems honor the file mode on Unix-domain socket files.

StreamLocalBindUnlink

Specifies whether to remove an existing Unix-domain socket file for local or remote port forwarding before creating a new one. If the socket file already exists and StreamLocalBindUnlink is not enabled, sshd will be unable to forward the port to the Unix-domain socket file. This option is only used for port forwarding to a Unix-domain socket file. The argument must be yes or no. The default is no.

StrictModes

Specifies whether sshd(8) should check file modes and ownership of the user's files and home directory before accepting login. This is normally desirable because novices sometimes accidentally leave their directory or files world-writable. The default is yes. Note that this does not apply to ChrootDirectory, whose permissions and ownership are checked unconditionally.

Subsystem

Configures an external subsystem (e.g. file transfer daemon). Arguments should be a subsystem name and a command (with optional arguments) to execute upon subsystem request. The command sftp-server implements the SFTP file transfer subsystem.

Alternately the name internal-sftp implements an in-process SFTP server. This may simplify configurations using ChrootDirectory to force a different filesystem root on clients.

By default no subsystems are defined.

SyslogFacility

Gives the facility code that is used when logging messages from sshd(8). The possible values are: DAEMON, USER, AUTH, AUTHPRIV, LOCAL0, LOCAL1, LOCAL2, LOCAL3, LOCAL4, LOCAL5, LOCAL6, LOCAL7. The default is AUTHPRIV.

TCPKeepAlive

Specifies whether the system should send TCP keepalive messages to the other side. If they are sent, death of the connection or crash of one of the machines will be properly noticed. However, this means that connections will die if the route is down temporarily, and some people find it annoying. On the other hand, if TCP keepalives are not sent, sessions may hang indefinitely on the server, leaving "ghost" users and consuming server resources. The default is yes (to send TCP keepalive messages), and the server will notice if the network goes down or the client host crashes. This avoids infinitely hanging sessions.

To disable TCP keepalive messages, the value should be set to no.

TrustedUserCAKeys

Specifies a file containing public keys of certificate authorities that are trusted to sign user certificates for authentication, or none to not use one. Keys are listed one per line; empty lines and comments starting with ‘#’ are allowed. If a certificate is presented for authentication and has its signing CA key listed in this file, then it may be used for authentication for any user listed in the certificate's principals list. Note that certificates that lack a list of principals will not be permitted for authentication using TrustedUserCAKeys. For more details on certificates, see the CERTIFICATES section in ssh-keygen(1).

UseDNS

Specifies whether sshd(8) should look up the remote host name, and to check that the resolved host name for the remote IP address maps back to the very same IP address. If this option is set to no (the default) then only addresses and not host names may be used in ~/.ssh/authorized_keys from and sshd_config Match Host directives.

UsePAM

Enables the Pluggable Authentication Module interface. If set to yes this will enable PAM authentication using ChallengeResponseAuthentication and PasswordAuthentication in addition to PAM account and session module processing for all authentication types. Because PAM challenge-response authentication usually serves an equivalent role to password authentication, you should disable either PasswordAuthentication or ChallengeResponseAuthentication.

If UsePAM is enabled, you will not be able to run sshd(8) as a non-root user. The default is yes.

VersionAddendum

Optionally specifies additional text to append to the SSH protocol banner sent by the server upon connection. The default is none.

X11DisplayOffset

Specifies the first display number available for sshd(8)'s X11 forwarding. This prevents sshd from interfering with real X11 servers. The default is 10.

X11Forwarding

Specifies whether X11 forwarding is permitted. The argument must be yes or no. The default is yes. When X11 forwarding is enabled, there may be additional exposure to the server and to client displays if the sshd(8) proxy display is configured to listen on the wildcard address (see X11UseLocalhost), though this is not the default. Additionally, the authentication spoofing and authentication data verification and substitution occur on the client side. The security risk of using X11 forwarding is that the client's X11 display server may be exposed to attack when the SSH client requests forwarding (see the warnings for ForwardX11 in ssh_config(5)). A system administrator may have a stance in which they want to protect clients that may expose themselves to attack by unwittingly requesting X11 forwarding, which can warrant a no setting.

Note that disabling X11 forwarding does not prevent users from forwarding X11 traffic, as users can always install their own forwarders.

X11UseLocalhost

Specifies whether sshd(8) should bind the X11 forwarding server to the loopback address or to the wildcard address. By default, sshd binds the forwarding server to the loopback address and sets the hostname part of the DISPLAY environment variable to localhost. This prevents remote hosts from connecting to the proxy display. However, some older X11 clients may not function with this configuration. X11UseLocalhost may be set to no to specify that the forwarding server should be bound to the wildcard address. The argument must be yes or no. The default is yes.

XAuthLocation

Specifies the full pathname of the xauth(1) program, or none to not use one. The default is /usr/bin/xauth.

## TIME FORMATS
sshd(8) command-line arguments and configuration file options that specify time may be expressed using a sequence of the form: time[qualifier], where time is a positive integer value and qualifier is one of the following:

⟨none⟩

seconds

s | S

seconds

m | M

minutes

h | H

hours

d | D

days

w | W

weeks

Each member of the sequence is added together to calculate the total time value.

Time format examples:

600

600 seconds (10 minutes)

10m

10 minutes

1h30m

1 hour 30 minutes (90 minutes)

## TOKENS
Arguments to some keywords can make use of tokens, which are expanded at runtime:

%%

A literal ‘%’.

%D

The routing domain in which the incoming connection was received.

%F

The fingerprint of the CA key.

%f

The fingerprint of the key or certificate.

%h

The home directory of the user.

%i

The key ID in the certificate.

%K

The base64-encoded CA key.

%k

The base64-encoded key or certificate for authentication.

%s

The serial number of the certificate.

%T

The type of the CA key.

%t

The key or certificate type.

%U

The numeric user ID of the target user.

%u

The username.

AuthorizedKeysCommand accepts the tokens %%, %f, %h, %k, %t, %U, and %u.

AuthorizedKeysFile accepts the tokens %%, %h, %U, and %u.

AuthorizedPrincipalsCommand accepts the tokens %%, %F, %f, %h, %i, %K, %k, %s, %T, %t, %U, and %u.

AuthorizedPrincipalsFile accepts the tokens %%, %h, %U, and %u.

ChrootDirectory accepts the tokens %%, %h, %U, and %u.

RoutingDomain accepts the token %D.

## FILES
/etc/openssh/sshd_config

Contains configuration data for sshd(8). This file should be writable by root only, but it is recommended (though not necessary) that it be world-readable.

## SEE ALSO
sftp-server(8), sshd(8)

## AUTHORS
OpenSSH is a derivative of the original and free ssh 1.2.12 release by Tatu Ylonen. Aaron Campbell, Bob Beck, Markus Friedl, Niels Provos, Theo de Raadt and Dug Song removed many bugs, re-added newer features and created OpenSSH. Markus Friedl contributed the support for SSH protocol versions 1.5 and 2.0. Niels Provos and Markus Friedl contributed support for privilege separation.


sslconfig

package: openssl

title: sslconfig(5)

text:
# sslconfig(5)

## NAME
config - OpenSSL CONF library configuration files

## DESCRIPTION
The OpenSSL CONF library can be used to read configuration files. It is used for the OpenSSL master configuration file openssl.cnf and in a few other places like SPKAC files and certificate extension files for the x509 utility. OpenSSL applications can also use the CONF library for their own purposes.

A configuration file is divided into a number of sections. Each section starts with a line [ section_name ] and ends when a new section is started or end of file is reached. A section name can consist of alphanumeric characters and underscores.

The first section of a configuration file is special and is referred to as the default section. This section is usually unnamed and spans from the start of file until the first named section. When a name is being looked up it is first looked up in a named section (if any) and then the default section.

The environment is mapped onto a section called ENV.

Comments can be included by preceding them with the # character

Other files can be included using the .include directive followed by a path. If the path points to a directory all files with names ending with .cnf or .conf are included from the directory. Recursive inclusion of directories from files in such directory is not supported. That means the files in the included directory can also contain .include directives but only inclusion of regular files is supported there. The inclusion of directories is not supported on systems without POSIX IO support.

It is strongly recommended to use absolute paths with the .include directive. Relative paths are evaluated based on the application current working directory so unless the configuration file containing the .include directive is application specific the inclusion will not work as expected.

There can be optional = character and whitespace characters between .include directive and the path which can be useful in cases the configuration file needs to be loaded by old OpenSSL versions which do not support the .include syntax. They would bail out with error if the = character is not present but with it they just ignore the include.

Each section in a configuration file consists of a number of name and value pairs of the form name=value

The name string can contain any alphanumeric characters as well as a few punctuation symbols such as . , ; and _.

The value string consists of the string following the = character until end of line with any leading and trailing white space removed.

The value string undergoes variable expansion. This can be done by including the form $var or ${var}: this will substitute the value of the named variable in the current section. It is also possible to substitute a value from another section using the syntax $section::name or ${section::name}. By using the form $ENV::name environment variables can be substituted. It is also possible to assign values to environment variables by using the name ENV::name, this will work if the program looks up environment variables using the CONF library instead of calling getenv() directly. The value string must not exceed 64k in length after variable expansion. Otherwise an error will occur.

It is possible to escape certain characters by using any kind of quote or the \ character. By making the last character of a line a \ a value string can be spread across multiple lines. In addition the sequences \n, \r, \b and \t are recognized.

All expansion and escape rules as described above that apply to value also apply to the path of the .include directive.

## OPENSSL LIBRARY CONFIGURATION
Applications can automatically configure certain aspects of OpenSSL using the master OpenSSL configuration file, or optionally an alternative configuration file. The openssl utility includes this functionality: any sub command uses the master OpenSSL configuration file unless an option is used in the sub command to use an alternative configuration file.

To enable library configuration the default section needs to contain an appropriate line which points to the main configuration section. The default name is openssl_conf which is used by the openssl utility. Other applications may use an alternative name such as myapplication_conf. All library configuration lines appear in the default section at the start of the configuration file.

The configuration section should consist of a set of name value pairs which contain specific module configuration information. The name represents the name of the configuration module. The meaning of the value is module specific: it may, for example, represent a further configuration section containing configuration module specific information. E.g.:

```
 # This must be in the default section
 openssl_conf = openssl_init
 [openssl_init]
 oid_section = new_oids
 engines = engine_section
 [new_oids]
 ... new oids here ...
 [engine_section]
 ... engine stuff here ...
```

The features of each configuration module are described below.

### ASN1 Object Configuration Module
This module has the name oid_section. The value of this variable points to a section containing name value pairs of OIDs: the name is the OID short and long name, the value is the numerical form of the OID. Although some of the openssl utility sub commands already have their own ASN1 OBJECT section functionality not all do. By using the ASN1 OBJECT configuration module all the openssl utility sub commands can see the new objects as well as any compliant applications. For example:

```
 [new_oids]
 some_new_oid = 1.2.3.4
 some_other_oid = 1.2.3.5
```

It is also possible to set the value to the long name followed by a comma and the numerical OID form. For example:

```
 shortName = some object long name, 1.2.3.4
```

### Engine Configuration Module
This ENGINE configuration module has the name engines. The value of this variable points to a section containing further ENGINE configuration information.

The section pointed to by engines is a table of engine names (though see engine_id below) and further sections containing configuration information specific to each ENGINE.

Each ENGINE specific section is used to set default algorithms, load dynamic, perform initialization and send ctrls. The actual operation performed depends on the command name which is the name of the name value pair. The currently supported commands are listed below.

For example:

```
 [engine_section]
 # Configure ENGINE named "foo"
 foo = foo_section
 # Configure ENGINE named "bar"
 bar = bar_section
 [foo_section]
 ... foo ENGINE specific commands ...
 [bar_section]
 ... "bar" ENGINE specific commands ...
```

The command engine_id is used to give the ENGINE name. If used this command must be first. For example:

```
 [engine_section]
 # This would normally handle an ENGINE named "foo"
 foo = foo_section
 [foo_section]
 # Override default name and use "myfoo" instead.
 engine_id = myfoo
```

The command dynamic_path loads and adds an ENGINE from the given path. It is equivalent to sending the ctrls SO_PATH with the path argument followed by LIST_ADD with value 2 and LOAD to the dynamic ENGINE. If this is not the required behaviour then alternative ctrls can be sent directly to the dynamic ENGINE using ctrl commands.

The command init determines whether to initialize the ENGINE. If the value is 0 the ENGINE will not be initialized, if 1 and attempt it made to initialized the ENGINE immediately. If the init command is not present then an attempt will be made to initialize the ENGINE after all commands in its section have been processed.

The command default_algorithms sets the default algorithms an ENGINE will supply using the functions ENGINE_set_default_string().

If the name matches none of the above command names it is assumed to be a ctrl command which is sent to the ENGINE. The value of the command is the argument to the ctrl command. If the value is the string EMPTY then no value is sent to the command.

For example:

```
 [engine_section]
 # Configure ENGINE named "foo"
 foo = foo_section
 [foo_section]
 # Load engine from DSO
 dynamic_path = /some/path/fooengine.so
 # A foo specific ctrl.
 some_ctrl = some_value
 # Another ctrl that doesn't take a value.
 other_ctrl = EMPTY
 # Supply all default algorithms
 default_algorithms = ALL
```

### EVP Configuration Module
This modules has the name alg_section which points to a section containing algorithm commands.

Currently the only algorithm command supported is fips_mode whose value can only be the boolean string off. If fips_mode is set to on, an error occurs as this library version is not FIPS capable.

### SSL Configuration Module
This module has the name ssl_conf which points to a section containing SSL configurations.

Each line in the SSL configuration section contains the name of the configuration and the section containing it.

Each configuration section consists of command value pairs for SSL_CONF. Each pair will be passed to a SSL_CTX or SSL structure if it calls SSL_CTX_config() or SSL_config() with the appropriate configuration name.

Note: any characters before an initial dot in the configuration section are ignored so the same command can be used multiple times.

For example:

```
 ssl_conf = ssl_sect
 [ssl_sect]
 server = server_section
 [server_section]
 RSA.Certificate = server-rsa.pem
 ECDSA.Certificate = server-ecdsa.pem
 Ciphers = ALL:!RC4
```

The system default configuration with name system_default if present will be applied during any creation of the SSL_CTX structure.

Example of a configuration with the system default:

```
 ssl_conf = ssl_sect
 [ssl_sect]
 system_default = system_default_sect
 [system_default_sect]
 MinProtocol = TLSv1.2
 MinProtocol = DTLSv1.2
```

## NOTES
If a configuration file attempts to expand a variable that doesn't exist then an error is flagged and the file will not load. This can happen if an attempt is made to expand an environment variable that doesn't exist. For example in a previous version of OpenSSL the default OpenSSL master configuration file used the value of HOME which may not be defined on non Unix systems and would cause an error.

This can be worked around by including a default section to provide a default value: then if the environment lookup fails the default value will be used instead. For this to work properly the default value must be defined earlier in the configuration file than the expansion. See the EXAMPLES section for an example of how to do this.

If the same variable exists in the same section then all but the last value will be silently ignored. In certain circumstances such as with DNs the same field may occur multiple times. This is usually worked around by ignoring any characters before an initial . e.g.

```
 1.OU="My first OU"
 2.OU="My Second OU"
```

## EXAMPLES
Here is a sample configuration file using some of the features mentioned above.

```
 # This is the default section.
 HOME=/temp
 RANDFILE= ${ENV::HOME}/.rnd
 configdir=$ENV::HOME/config
 [ section_one ]
 # We are now in section one.
 # Quotes permit leading and trailing whitespace
 any = " any variable name "
 other = A string that can \
 cover several lines \
 by including \\ characters
 message = Hello World\n
 [ section_two ]
 greeting = $section_one::message
```

This next example shows how to expand environment variables safely.

Suppose you want a variable called tmpfile to refer to a temporary filename. The directory it is placed in can determined by the TEMP or TMP environment variables but they may not be set to any value at all. If you just include the environment variable names and the variable doesn't exist then this will cause an error when an attempt is made to load the configuration file. By making use of the default section both values can be looked up with TEMP taking priority and /tmp used if neither is defined:

```
 TMP=/tmp
 # The above value is used if TMP isn't in the environment
 TEMP=$ENV::TMP
 # The above value is used if TEMP isn't in the environment
 tmpfile=${ENV::TEMP}/tmp.filename
```

Simple OpenSSL library configuration example to enter FIPS mode:

```
 # Default appname: should match "appname" parameter (if any)
 # supplied to CONF_modules_load_file et al.
 openssl_conf = openssl_conf_section
 [openssl_conf_section]
 # Configuration module list
 alg_section = evp_sect
 [evp_sect]
 # Set to "yes" to enter FIPS mode if supported
 fips_mode = yes
```

Note: in the above example you will get an error in non FIPS capable versions of OpenSSL.

Simple OpenSSL library configuration to make TLS 1.2 and DTLS 1.2 the system-default minimum TLS and DTLS versions, respectively:

```
 # Toplevel section for openssl (including libssl)
 openssl_conf = default_conf_section
 [default_conf_section]
 # We only specify configuration for the "ssl module"
 ssl_conf = ssl_section
 [ssl_section]
 system_default = system_default_section
 [system_default_section]
 MinProtocol = TLSv1.2
 MinProtocol = DTLSv1.2
```

The minimum TLS protocol is applied to SSL_CTX objects that are TLS-based, and the minimum DTLS protocol to those are DTLS-based. The same applies also to maximum versions set with MaxProtocol.

More complex OpenSSL library configuration. Add OID and don't enter FIPS mode:

```
 # Default appname: should match "appname" parameter (if any)
 # supplied to CONF_modules_load_file et al.
 openssl_conf = openssl_conf_section
 [openssl_conf_section]
 # Configuration module list
 alg_section = evp_sect
 oid_section = new_oids
 [evp_sect]
 # This will have no effect as FIPS mode is off by default.
 # Set to "yes" to enter FIPS mode, if supported
 fips_mode = no
 [new_oids]
 # New OID, just short name
 newoid1 = 1.2.3.4.1
 # New OID shortname and long name
 newoid2 = New OID 2 long name, 1.2.3.4.2
```

The above examples can be used with any application supporting library configuration if "openssl_conf" is modified to match the appropriate "appname".

For example if the second sample file above is saved to "example.cnf" then the command line:

```
 OPENSSL_CONF=example.cnf openssl asn1parse -genstr OID:1.2.3.4.1
```

will output:

```
    0:d=0  hl=2 l=   4 prim: OBJECT            :newoid1
```

showing that the OID "newoid1" has been added as "1.2.3.4.1".

## ENVIRONMENT
OPENSSL_CONF

The path to the config file. Ignored in set-user-ID and set-group-ID programs.

OPENSSL_ENGINES

The path to the engines directory. Ignored in set-user-ID and set-group-ID programs.

## BUGS
Currently there is no way to include characters using the octal \nnn form. Strings are all null terminated so nulls cannot form part of the value.

The escaping isn't quite right: if you want to use sequences like \n you can't use any quote escaping on the same line.

Files are loaded in a single pass. This means that a variable expansion will only work if the variables referenced are defined earlier in the file.

## SEE ALSO
x509(1), req(1), ca(1)

## COPYRIGHT
Copyright 2000-2020 The OpenSSL Project Authors. All Rights Reserved.

Licensed under the OpenSSL license (the "License"). You may not use this file except in compliance with the License. You can obtain a copy in the file LICENSE in the source distribution or at <https://www.openssl.org/source/license.html>.


title: x509v3_config(5)

text:
# x509v3_config(5)

## NAME
x509v3_config - X509 V3 certificate extension configuration format

## DESCRIPTION
Several of the OpenSSL utilities can add extensions to a certificate or certificate request based on the contents of a configuration file.

Typically the application will contain an option to point to an extension section. Each line of the extension section takes the form:

```
 extension_name=[critical,] extension_options
```

If critical is present then the extension will be critical.

The format of extension_options depends on the value of extension_name.

There are four main types of extension: string extensions, multi-valued extensions, raw and arbitrary extensions.

String extensions simply have a string which contains either the value itself or how it is obtained.

For example:

```
 nsComment="This is a Comment"
```

Multi-valued extensions have a short form and a long form. The short form is a list of names and values:

```
 basicConstraints=critical,CA:true,pathlen:1
```

The long form allows the values to be placed in a separate section:

```
 basicConstraints=critical,@bs_section
 [bs_section]
 CA=true
 pathlen=1
```

Both forms are equivalent.

The syntax of raw extensions is governed by the extension code: it can for example contain data in multiple sections. The correct syntax to use is defined by the extension code itself: check out the certificate policies extension for an example.

If an extension type is unsupported then the arbitrary extension syntax must be used, see the ARBITRARY EXTENSIONS section for more details.

## STANDARD EXTENSIONS
The following sections describe each supported extension in detail.

### Basic Constraints.
This is a multi valued extension which indicates whether a certificate is a CA certificate. The first (mandatory) name is CA followed by TRUE or FALSE. If CA is TRUE then an optional pathlen name followed by a nonnegative value can be included.

For example:

```
 basicConstraints=CA:TRUE
 basicConstraints=CA:FALSE
 basicConstraints=critical,CA:TRUE, pathlen:0
```

A CA certificate must include the basicConstraints value with the CA field set to TRUE. An end user certificate must either set CA to FALSE or exclude the extension entirely. Some software may require the inclusion of basicConstraints with CA set to FALSE for end entity certificates.

The pathlen parameter indicates the maximum number of CAs that can appear below this one in a chain. So if you have a CA with a pathlen of zero it can only be used to sign end user certificates and not further CAs.

### Key Usage.
Key usage is a multi valued extension consisting of a list of names of the permitted key usages.

The supported names are: digitalSignature, nonRepudiation, keyEncipherment, dataEncipherment, keyAgreement, keyCertSign, cRLSign, encipherOnly and decipherOnly.

Examples:

```
 keyUsage=digitalSignature, nonRepudiation
 keyUsage=critical, keyCertSign
```

### Extended Key Usage.
This extensions consists of a list of usages indicating purposes for which the certificate public key can be used for,

These can either be object short names or the dotted numerical form of OIDs. While any OID can be used only certain values make sense. In particular the following PKIX, NS and MS values are meaningful:

```
 Value                  Meaning
 -----                  -------
 serverAuth             SSL/TLS Web Server Authentication.
 clientAuth             SSL/TLS Web Client Authentication.
 codeSigning            Code signing.
 emailProtection        E-mail Protection (S/MIME).
 timeStamping           Trusted Timestamping
 OCSPSigning            OCSP Signing
 ipsecIKE               ipsec Internet Key Exchange
 msCodeInd              Microsoft Individual Code Signing (authenticode)
 msCodeCom              Microsoft Commercial Code Signing (authenticode)
 msCTLSign              Microsoft Trust List Signing
 msEFS                  Microsoft Encrypted File System
```

Examples:

```
 extendedKeyUsage=critical,codeSigning,1.2.3.4
 extendedKeyUsage=serverAuth,clientAuth
```

### Subject Key Identifier.
This is really a string extension and can take two possible values. Either the word hash which will automatically follow the guidelines in RFC3280 or a hex string giving the extension value to include. The use of the hex string is strongly discouraged.

Example:

```
 subjectKeyIdentifier=hash
```

### Authority Key Identifier.
The authority key identifier extension permits two options. keyid and issuer: both can take the optional value "always".

If the keyid option is present an attempt is made to copy the subject key identifier from the parent certificate. If the value "always" is present then an error is returned if the option fails.

The issuer option copies the issuer and serial number from the issuer certificate. This will only be done if the keyid option fails or is not included unless the "always" flag will always include the value.

Example:

```
 authorityKeyIdentifier=keyid,issuer
```

### Subject Alternative Name.
The subject alternative name extension allows various literal values to be included in the configuration file. These include email (an email address) URI a uniform resource indicator, DNS (a DNS domain name), RID (a registered ID: OBJECT IDENTIFIER), IP (an IP address), dirName (a distinguished name) and otherName.

The email option include a special 'copy' value. This will automatically include any email addresses contained in the certificate subject name in the extension.

The IP address used in the IP options can be in either IPv4 or IPv6 format.

The value of dirName should point to a section containing the distinguished name to use as a set of name value pairs. Multi values AVAs can be formed by prefacing the name with a + character.

otherName can include arbitrary data associated with an OID: the value should be the OID followed by a semicolon and the content in standard ASN1_generate_nconf(3) format.

Examples:

```
 subjectAltName=email:copy,email:my@other.address,URI:http://my.url.here/
 subjectAltName=IP:192.168.7.1
 subjectAltName=IP:13::17
 subjectAltName=email:my@other.address,RID:1.2.3.4
 subjectAltName=otherName:1.2.3.4;UTF8:some other identifier
 subjectAltName=dirName:dir_sect
 [dir_sect]
 C=UK
 O=My Organization
 OU=My Unit
 CN=My Name
```

### Issuer Alternative Name.
The issuer alternative name option supports all the literal options of subject alternative name. It does not support the email:copy option because that would not make sense. It does support an additional issuer:copy option that will copy all the subject alternative name values from the issuer certificate (if possible).

Example:

```
 issuerAltName = issuer:copy
```

### Authority Info Access.
The authority information access extension gives details about how to access certain information relating to the CA. Its syntax is accessOID;location where location has the same syntax as subject alternative name (except that email:copy is not supported). accessOID can be any valid OID but only certain values are meaningful, for example OCSP and caIssuers.

Example:

```
 authorityInfoAccess = OCSP;URI:http://ocsp.my.host/
 authorityInfoAccess = caIssuers;URI:http://my.ca/ca.html
```

### CRL distribution points
This is a multi-valued extension whose options can be either in name:value pair using the same form as subject alternative name or a single value representing a section name containing all the distribution point fields.

For a name:value pair a new DistributionPoint with the fullName field set to the given value both the cRLissuer and reasons fields are omitted in this case.

In the single option case the section indicated contains values for each field. In this section:

If the name is "fullname" the value field should contain the full name of the distribution point in the same format as subject alternative name.

If the name is "relativename" then the value field should contain a section name whose contents represent a DN fragment to be placed in this field.

The name "CRLIssuer" if present should contain a value for this field in subject alternative name format.

If the name is "reasons" the value field should consist of a comma separated field containing the reasons. Valid reasons are: "keyCompromise", "CACompromise", "affiliationChanged", "superseded", "cessationOfOperation", "certificateHold", "privilegeWithdrawn" and "AACompromise".

Simple examples:

```
 crlDistributionPoints=URI:http://myhost.com/myca.crl
 crlDistributionPoints=URI:http://my.com/my.crl,URI:http://oth.com/my.crl
```

Full distribution point example:

```
 crlDistributionPoints=crldp1_section
 [crldp1_section]
 fullname=URI:http://myhost.com/myca.crl
 CRLissuer=dirName:issuer_sect
 reasons=keyCompromise, CACompromise
 [issuer_sect]
 C=UK
 O=Organisation
 CN=Some Name
```

### Issuing Distribution Point
This extension should only appear in CRLs. It is a multi valued extension whose syntax is similar to the "section" pointed to by the CRL distribution points extension with a few differences.

The names "reasons" and "CRLissuer" are not recognized.

The name "onlysomereasons" is accepted which sets this field. The value is in the same format as the CRL distribution point "reasons" field.

The names "onlyuser", "onlyCA", "onlyAA" and "indirectCRL" are also accepted the values should be a boolean value (TRUE or FALSE) to indicate the value of the corresponding field.

Example:

```
 issuingDistributionPoint=critical, @idp_section
 [idp_section]
 fullname=URI:http://myhost.com/myca.crl
 indirectCRL=TRUE
 onlysomereasons=keyCompromise, CACompromise
 [issuer_sect]
 C=UK
 O=Organisation
 CN=Some Name
```

### Certificate Policies.
This is a raw extension. All the fields of this extension can be set by using the appropriate syntax.

If you follow the PKIX recommendations and just using one OID then you just include the value of that OID. Multiple OIDs can be set separated by commas, for example:

```
 certificatePolicies= 1.2.4.5, 1.1.3.4
```

If you wish to include qualifiers then the policy OID and qualifiers need to be specified in a separate section: this is done by using the @section syntax instead of a literal OID value.

The section referred to must include the policy OID using the name policyIdentifier, cPSuri qualifiers can be included using the syntax:

```
 CPS.nnn=value
```

userNotice qualifiers can be set using the syntax:

```
 userNotice.nnn=@notice
```

The value of the userNotice qualifier is specified in the relevant section. This section can include explicitText, organization and noticeNumbers options. explicitText and organization are text strings, noticeNumbers is a comma separated list of numbers. The organization and noticeNumbers options (if included) must BOTH be present. If you use the userNotice option with IE5 then you need the 'ia5org' option at the top level to modify the encoding: otherwise it will not be interpreted properly.

Example:

```
 certificatePolicies=ia5org,1.2.3.4,1.5.6.7.8,@polsect
 [polsect]
 policyIdentifier = 1.3.5.8
 CPS.1="http://my.host.name/"
 CPS.2="http://my.your.name/"
 userNotice.1=@notice
 [notice]
 explicitText="Explicit Text Here"
 organization="Organisation Name"
 noticeNumbers=1,2,3,4
```

The ia5org option changes the type of the organization field. In RFC2459 it can only be of type DisplayText. In RFC3280 IA5String is also permissible. Some software (for example some versions of MSIE) may require ia5org.

ASN1 type of explicitText can be specified by prepending UTF8, BMP or VISIBLE prefix followed by colon. For example:

```
 [notice]
 explicitText="UTF8:Explicit Text Here"
```

### Policy Constraints
This is a multi-valued extension which consisting of the names requireExplicitPolicy or inhibitPolicyMapping and a non negative integer value. At least one component must be present.

Example:

```
 policyConstraints = requireExplicitPolicy:3
```

### Inhibit Any Policy
This is a string extension whose value must be a non negative integer.

Example:

```
 inhibitAnyPolicy = 2
```

### Name Constraints
The name constraints extension is a multi-valued extension. The name should begin with the word permitted or excluded followed by a ;. The rest of the name and the value follows the syntax of subjectAltName except email:copy is not supported and the IP form should consist of an IP addresses and subnet mask separated by a /.

Examples:

```
 nameConstraints=permitted;IP:192.168.0.0/255.255.0.0
 nameConstraints=permitted;email:.somedomain.com
 nameConstraints=excluded;email:.com
```

### OCSP No Check
The OCSP No Check extension is a string extension but its value is ignored.

Example:

```
 noCheck = ignored
```

### TLS Feature (aka Must Staple)
This is a multi-valued extension consisting of a list of TLS extension identifiers. Each identifier may be a number (0..65535) or a supported name. When a TLS client sends a listed extension, the TLS server is expected to include that extension in its reply.

The supported names are: status_request and status_request_v2.

Example:

```
 tlsfeature = status_request
```

## DEPRECATED EXTENSIONS
The following extensions are non standard, Netscape specific and largely obsolete. Their use in new applications is discouraged.

### Netscape String extensions.
Netscape Comment (nsComment) is a string extension containing a comment which will be displayed when the certificate is viewed in some browsers.

Example:

```
 nsComment = "Some Random Comment"
```

Other supported extensions in this category are: nsBaseUrl, nsRevocationUrl, nsCaRevocationUrl, nsRenewalUrl, nsCaPolicyUrl and nsSslServerName.

### Netscape Certificate Type
This is a multi-valued extensions which consists of a list of flags to be included. It was used to indicate the purposes for which a certificate could be used. The basicConstraints, keyUsage and extended key usage extensions are now used instead.

Acceptable values for nsCertType are: client, server, email, objsign, reserved, sslCA, emailCA, objCA.

## ARBITRARY EXTENSIONS
If an extension is not supported by the OpenSSL code then it must be encoded using the arbitrary extension format. It is also possible to use the arbitrary format for supported extensions. Extreme care should be taken to ensure that the data is formatted correctly for the given extension type.

There are two ways to encode arbitrary extensions.

The first way is to use the word ASN1 followed by the extension content using the same syntax as ASN1_generate_nconf(3). For example:

```
 1.2.3.4=critical,ASN1:UTF8String:Some random data
 1.2.3.4=ASN1:SEQUENCE:seq_sect
 [seq_sect]
 field1 = UTF8:field1
 field2 = UTF8:field2
```

It is also possible to use the word DER to include the raw encoded data in any extension.

```
 1.2.3.4=critical,DER:01:02:03:04
 1.2.3.4=DER:01020304
```

The value following DER is a hex dump of the DER encoding of the extension Any extension can be placed in this form to override the default behaviour. For example:

```
 basicConstraints=critical,DER:00:01:02:03
```

## WARNINGS
There is no guarantee that a specific implementation will process a given extension. It may therefore be sometimes possible to use certificates for purposes prohibited by their extensions because a specific application does not recognize or honour the values of the relevant extensions.

The DER and ASN1 options should be used with caution. It is possible to create totally invalid extensions if they are not used carefully.

## NOTES
If an extension is multi-value and a field value must contain a comma the long form must be used otherwise the comma would be misinterpreted as a field separator. For example:

```
 subjectAltName=URI:ldap://somehost.com/CN=foo,OU=bar
```

will produce an error but the equivalent form:

```
 subjectAltName=@subject_alt_section
 [subject_alt_section]
 subjectAltName=URI:ldap://somehost.com/CN=foo,OU=bar
```

is valid.

Due to the behaviour of the OpenSSL conf library the same field name can only occur once in a section. This means that:

```
 subjectAltName=@alt_section
 [alt_section]
 email=steve@here
 email=steve@there
```

will only recognize the last value. This can be worked around by using the form:

```
 [alt_section]
 email.1=steve@here
 email.2=steve@there
```

## SEE ALSO
req(1), ca(1), x509(1), ASN1_generate_nconf(3)

## COPYRIGHT
Copyright 2004-2020 The OpenSSL Project Authors. All Rights Reserved.

Licensed under the OpenSSL license (the "License"). You may not use this file except in compliance with the License. You can obtain a copy in the file LICENSE in the source distribution or at <https://www.openssl.org/source/license.html>.


package: openssl-LibreSSL

title: x509v3-LibreSSL.cnf(5)

text:
# x509v3-LibreSSL.cnf(5)

## NAME
x509v3.cnf — X.509 V3 certificate extension configuration format

## DESCRIPTION
Several of the OpenSSL utilities can add extensions to a certificate or certificate request based on the contents of a configuration file. The file format is based on the openssl.cnf(5) format.

Typically the application will contain an option to point to an extension section. Each line of the extension section takes the form:

extension_name=[critical,] extension_options

If critical is present, then the extension will be critical.

The format of extension_options depends on the value of extension_name.

There are four main types of extension: string extensions, multi-valued extensions, raw extensions, and arbitrary extensions.

String extensions simply have a string which contains either the value itself or how it is obtained. For example:

nsComment="This is a Comment"

Multi-valued extensions have a short form and a long form. The short form is a list of names and values:

basicConstraints=critical,CA:true,pathlen:1

The long form allows the values to be placed in a separate section:

```
basicConstraints=critical,@bs_section

[bs_section]
CA=true
pathlen=1
```

Both forms are equivalent.

The syntax of raw extensions is governed by the extension code: it can for example contain data in multiple sections. The correct syntax to use is defined by the extension code itself: check out the certificate policies extension for an example.

If an extension type is unsupported, then the arbitrary extension syntax must be used; see the ARBITRARY EXTENSIONS section for more details.

## STANDARD EXTENSIONS
The following sections describe each supported extension in detail.

### Basic constraints
This is a multi-valued extension which indicates whether a certificate is a CA certificate. The first (mandatory) name is CA followed by TRUE or FALSE. If CA is TRUE, then an optional pathlen name followed by a non-negative value can be included. For example:

```
basicConstraints=CA:TRUE
basicConstraints=CA:FALSE
basicConstraints=critical,CA:TRUE, pathlen:0
```

A CA certificate must include the basicConstraints value with the CA field set to TRUE. An end user certificate must either set CA to FALSE or exclude the extension entirely. Some software may require the inclusion of basicConstraints with CA set to FALSE for end entity certificates.

The pathlen parameter indicates the maximum number of CAs that can appear below this one in a chain. So if you have a CA with a pathlen of zero, it can only be used to sign end user certificates and not further CAs.

### Key usage
Key usage is a multi-valued extension consisting of a list of names of the permitted key usages.

The supported names are: digitalSignature, nonRepudiation, keyEncipherment, dataEncipherment, keyAgreement, keyCertSign, cRLSign, encipherOnly, and decipherOnly. Examples:

```
keyUsage=digitalSignature, nonRepudiation
keyUsage=critical, keyCertSign
```

### Extended key usage
This extension consists of a list of purposes for which the certificate public key can be used.

These can either be object short names or the dotted numerical form of OIDs. While any OID can be used, only certain values make sense. In particular the following PKIX, NS and MS values are meaningful:

value

meaning

serverAuth

TLS server authentication

clientAuth

TLS client authentication

codeSigning

code signing

emailProtection

E-mail protection (S/MIME)

timeStamping

trusted timestamping

OCSPSigning

OCSP signing

ipsecIKE

IPsec internet key exchange

msCodeInd

Microsoft individual code signing (authenticode)

msCodeCom

Microsoft commercial code signing (authenticode)

msCTLSign

Microsoft trust list signing

msEFS

Microsoft encrypted file system

Examples:

```
extendedKeyUsage=critical,codeSigning,1.2.3.4
extendedKeyUsage=serverAuth,clientAuth
```

### Subject key identifier
This is really a string extension and can take two possible values. Either the word hash which will automatically follow the guidelines in RFC 3280 or a hex string giving the extension value to include. The use of the hex string is strongly discouraged. Example:

subjectKeyIdentifier=hash

### Authority key identifier
The authority key identifier extension permits two options, keyid and issuer: both can take the optional value always.

If the keyid option is present, an attempt is made to copy the subject key identifier from the parent certificate. If the value always is present, then an error is returned if the option fails.

The issuer option copies the issuer and serial number from the issuer certificate. This will only be done if the keyid option fails or is not included unless the always flag will always include the value. Example:

authorityKeyIdentifier=keyid,issuer

### Subject alternative name
The subject alternative name extension allows various literal values to be included in the configuration file. These include email (an email address), URI (a uniform resource indicator), DNS (a DNS domain name), RID (a registered ID: OBJECT IDENTIFIER), IP (an IP address), dirName (a distinguished name), and otherName.

The email option can include a special copy value. This will automatically include any email addresses contained in the certificate subject name in the extension.

The IP address used in the IP options can be in either IPv4 or IPv6 format.

The value of dirName should point to a section containing the distinguished name to use as a set of name value pairs. Multi values AVAs can be formed by prefacing the name with a ‘+’ character.

otherName can include arbitrary data associated with an OID: the value should be the OID followed by a semicolon and the content in standard ASN1_generate_nconf(3) format. Examples:

```
subjectAltName=email:copy,email:my@other.address,URI:http://my.url.here/
subjectAltName=IP:192.168.7.1
subjectAltName=IP:13::17
subjectAltName=email:my@other.address,RID:1.2.3.4
subjectAltName=otherName:1.2.3.4;UTF8:some other identifier

subjectAltName=dirName:dir_sect

[dir_sect]
C=UK
O=My Organization
OU=My Unit
CN=My Name
```

### Issuer alternative name
The issuer alternative name option supports all the literal options of subject alternative name. It does not support the email:copy option because that would not make sense. It does support an additional issuer:copy option that will copy all the subject alternative name values from the issuer certificate (if possible). Example:

issuerAltName = issuer:copy

### Authority info access
The authority information access extension gives details about how to access certain information relating to the CA. Its syntax is accessOID; location where location has the same syntax as subject alternative name (except that email:copy is not supported). accessOID can be any valid OID but only certain values are meaningful, for example OCSP and caIssuers. Example:

```
authorityInfoAccess = OCSP;URI:http://ocsp.my.host/
authorityInfoAccess = caIssuers;URI:http://my.ca/ca.html
```

### CRL distribution points
This is a multi-valued extension whose options can be either in name:value pair form using the same form as subject alternative name or a single value representing a section name containing all the distribution point fields.

For a name:value pair a new DistributionPoint with the fullName field set to the given value, both the cRLissuer and reasons fields are omitted in this case.

In the single option case, the section indicated contains values for each field. In this section:

If the name is fullname, the value field should contain the full name of the distribution point in the same format as subject alternative name.

If the name is relativename, then the value field should contain a section name whose contents represent a DN fragment to be placed in this field.

The name CRLIssuer, if present, should contain a value for this field in subject alternative name format.

If the name is reasons, the value field should consist of a comma separated field containing the reasons. Valid reasons are: keyCompromise, CACompromise, affiliationChanged, superseded, cessationOfOperation, certificateHold, privilegeWithdrawn, and AACompromise.

Simple examples:

```
crlDistributionPoints=URI:http://myhost.com/myca.crl
crlDistributionPoints=URI:http://my.com/my.crl,URI:http://oth.com/my.crl
```

Full distribution point example:

```
crlDistributionPoints=crldp1_section

[crldp1_section]
fullname=URI:http://myhost.com/myca.crl
CRLissuer=dirName:issuer_sect
reasons=keyCompromise, CACompromise

[issuer_sect]
C=UK
O=Organisation
CN=Some Name
```

### Issuing distribution point
This extension should only appear in CRLs. It is a multi-valued extension whose syntax is similar to the "section" pointed to by the CRL distribution points extension with a few differences.

The names reasons and CRLissuer are not recognized.

The name onlysomereasons is accepted, which sets this field. The value is in the same format as the CRL distribution point reasons field.

The names onlyuser, onlyCA, onlyAA, and indirectCRL are also accepted. The values should be a boolean values (TRUE or FALSE) to indicate the value of the corresponding field. Example:

```
issuingDistributionPoint=critical, @idp_section

[idp_section]
fullname=URI:http://myhost.com/myca.crl
indirectCRL=TRUE
onlysomereasons=keyCompromise, CACompromise

[issuer_sect]
C=UK
O=Organisation
CN=Some Name
```

### Certificate policies
This is a raw extension. All the fields of this extension can be set by using the appropriate syntax.

If you follow the PKIX recommendations and just use one OID, then you just include the value of that OID. Multiple OIDs can be set separated by commas, for example:

certificatePolicies= 1.2.4.5, 1.1.3.4

If you wish to include qualifiers, then the policy OID and qualifiers need to be specified in a separate section: this is done by using the @section syntax instead of a literal OID value.

The section referred to must include the policy OID using the name policyIdentifier. CPSuri qualifiers can be included using the syntax:

CPS.nnn=value

userNotice qualifiers can be set using the syntax:

userNotice.nnn=@notice

The value of the userNotice qualifier is specified in the relevant section. This section can include explicitText, organization, and noticeNumbers options. explicitText and organization are text strings, and noticeNumbers is a comma separated list of numbers. The organization and noticeNumbers options (if included) must both be present. If you use the userNotice option with IE5 then you need the ia5org option at the top level to modify the encoding: otherwise it will not be interpreted properly. Example:

```
certificatePolicies=ia5org,1.2.3.4,1.5.6.7.8,@polsect

[polsect]
policyIdentifier = 1.3.5.8
CPS.1="http://my.host.name/"
CPS.2="http://my.your.name/"
userNotice.1=@notice

[notice]
explicitText="Explicit Text Here"
organization="Organisation Name"
noticeNumbers=1,2,3,4
```

The ia5org option changes the type of the organization field. In RFC 2459, it can only be of type DisplayText. In RFC 3280, IA5String is also permissible. Some software (for example some versions of MSIE) may require ia5org.

### Policy constraints
This is a multi-valued extension which consists of the names requireExplicitPolicy or inhibitPolicyMapping and a non-negative integer value. At least one component must be present. Example:

policyConstraints = requireExplicitPolicy:3

### Inhibit any policy
This is a string extension whose value must be a non-negative integer. Example:

inhibitAnyPolicy = 2

### Name constraints
The name constraints extension is a multi-valued extension. The name should begin with the word permitted or excluded, followed by a semicolon. The rest of the name and the value follows the syntax of subjectAltName except email:copy is not supported and the IP form should consist of an IP addresses and subnet mask separated by a slash. Examples:

```
nameConstraints=permitted;IP:192.168.0.0/255.255.0.0
nameConstraints=permitted;email:.somedomain.com
nameConstraints=excluded;email:.com
```

### OCSP no check
The OCSP no check extension is a string extension, but its value is ignored. Example:

noCheck = ignored

### TLS Feature (aka must staple)
This is a multi-valued extension consisting of a list of TLS extension identifiers. Each identifier may be a number in the range from 0 to 65535 or a supported name. When a TLS client sends a listed extension, the TLS server is expected to include that extension in its reply.

The supported names are: status_request and status_request_v2. Example:

tlsfeature = status_request

## DEPRECATED EXTENSIONS
The following extensions are non-standard, Netscape specific and largely obsolete. Their use in new applications is discouraged.

### Netscape string extensions
Netscape comment (nsComment) is a string extension containing a comment which will be displayed when the certificate is viewed in some browsers. Example:

nsComment = Some Random Comment

Other supported extensions in this category are: nsBaseUrl, nsRevocationUrl, nsCaRevocationUrl, nsRenewalUrl, nsCaPolicyUrl, and nsSslServerName.

### Netscape certificate type
This is a multi-valued extensions which consists of a list of flags to be included. It was used to indicate the purposes for which a certificate could be used. The basicConstraints, keyUsage, and extended key usage extensions are now used instead.

Acceptable values for nsCertType are: client, server, email, objsign, reserved, sslCA, emailCA, objCA.

## ARBITRARY EXTENSIONS
If an extension is not supported by the OpenSSL code, then it must be encoded using the arbitrary extension format. It is also possible to use the arbitrary format for supported extensions. Extreme care should be taken to ensure that the data is formatted correctly for the given extension type.

There are two ways to encode arbitrary extensions.

The first way is to use the word ASN1 followed by the extension content using the same syntax as ASN1_generate_nconf(3). For example:

```
1.2.3.4=critical,ASN1:UTF8String:Some random data
1.2.3.4=ASN1:SEQUENCE:seq_sect

[seq_sect]
field1 = UTF8:field1
field2 = UTF8:field2
```

It is also possible to use the word DER to include the raw encoded data in any extension.

```
1.2.3.4=critical,DER:01:02:03:04
1.2.3.4=DER:01020304
```

The value following DER is a hex dump of the DER encoding of the extension. Any extension can be placed in this form to override the default behaviour. For example:

basicConstraints=critical,DER:00:01:02:03

## FILES
/etc/libressl/x509v3.cnf

standard configuration file

## SEE ALSO
openssl-LibreSSL(1), ASN1_generate_nconf(3), OPENSSL_config(3), openssl.cnf(5)

## HISTORY
X509v3 extension code was first added to OpenSSL 0.9.2.

## CAVEATS
There is no guarantee that a specific implementation will process a given extension. It may therefore sometimes be possible to use certificates for purposes prohibited by their extensions because a specific application does not recognize or honour the values of the relevant extensions.

The DER and ASN1 options should be used with caution. It is possible to create totally invalid extensions if they are not used carefully.

If an extension is multi-value and a field value must contain a comma, the long form must be used. Otherwise the comma would be misinterpreted as a field separator. For example,

subjectAltName=URI:ldap://somehost.com/CN=foo,OU=bar

will produce an error, but the following form is valid:

```
subjectAltName=@subject_alt_section

[subject_alt_section]
subjectAltName=URI:ldap://somehost.com/CN=foo,OU=bar
```

Due to the behaviour of the OpenSSL CONF library, the same field name can only occur once in a section. That means that

```
subjectAltName=@alt_section

[alt_section]
email=steve@here
email=steve@there
```

will only use the last value. This can be worked around by using the form:

```
[alt_section]
email.1=steve@here
email.2=steve@there
```


dispersion.conf

package: openstack-swift

title: dispersion.conf(5)

text:
# dispersion.conf(5)

## NAME
dispersion.conf - configuration file for the OpenStack Swift dispersion tools

## SYNOPSIS
dispersion.conf

## DESCRIPTION
This is the configuration file used by the dispersion populate and report tools. The file format consists of the '[dispersion]' module as the header and available parameters. Any line that begins with a '#' symbol is ignored.

## PARAMETERS
auth_version

Authentication system API version. The default is 1.0.

auth_url

Authentication system URL

auth_user

Authentication system account/user name

auth_key

Authentication system account/user password

project_name

Project name in case of keystone auth version 3

project_domain_name

Project domain name in case of keystone auth version 3

user_domain_name

User domain name in case of keystone auth version 3

endpoint_type

The default is 'publicURL'.

keystone_api_insecure

The default is false.

swift_dir

Location of OpenStack Swift configuration and ring files

dispersion_coverage

Percentage of partition coverage to use. The default is 1.0.

retries

Maximum number of attempts. The defaul is 5.

concurrency

Concurrency to use. The default is 25.

container_populate

The default is true.

object_populate

The default is true.

dump_json

Whether to output in json format. The default is no.

container_report

Whether to run the container report. The default is yes.

object_report

Whether to run the object report. The default is yes.

## SAMPLE
[dispersion]

auth_url = https://127.0.0.1:443/auth/v1.0

auth_user = dpstats:dpstats

auth_key = dpstats

swift_dir = /etc/swift

\# keystone_api_insecure = no

\# project_name = dpstats

\# project_domain_name = default

\# user_domain_name = default

\# dispersion_coverage = 1.0

\# retries = 5

\# concurrency = 25

\# dump_json = no

\# container_report = yes

\# object_report = yes

## DOCUMENTATION
More in depth documentation about the swift-dispersion utilities and also OpenStack Swift as a whole can be found at https://docs.openstack.org/swift/latest/admin_guide.html#dispersion-report and https://docs.openstack.org/swift/latest/

## SEE ALSO
swift-dispersion-report(1), swift-dispersion-populate(1)